A medium energy ion scattering spectroscopy(ME1S) system has been developed and tested.In the MEIS system a toroidal electrostatic energy analyzer(TEA) and a two dimensional position sensitivedetector(PSD) were used. The energy resolution of MEIS system was estimated to be less than $4 imes 10^{-3}$ and the overall angular resolution was less than 0.3". From the MEIS spectrum of $Ta_2O_5$(300 $AA$)/ onSi analyzedousing 60 keV $H^+$, the energy loss factor(S.1 and depth resolution were estimated to he 42 eV/$AA$ and 9.7 $AA$, respectively. Also Si(100) surface was analyzed using the MEIS system. A random MElSspectrum was obtained from thc Si(100) covered with native oxide layers. At the double alignment condition, MElS spectrum showed ;i Si surface peak, a oxygen peak and a carbon peak.nd a carbon peak.